Master compass



Feb. 19, 1929.

E. L. HOLMES MASTER COMPASS Original Filed Jan. 23, 1925 I 3Sheets-Sheet 6 INVENTOR ATTORNEY Feb. 19, 1929. 1,702,405

E. L. HOLMES MASTER COMPASS Original Filed Jan. 23, 1925 3 Sheets-Sheet2 l||-. -\-n \l-llm- -ln -Ir 'i IllllllII-IIIIIIIIlllllllllllllllllllllIIIH Vi a "x mwzwz ATTORNEY Feb. 19, 1929.

E. L. HOLMES MASTER COMPASS Original Filed Jan. 23, 1925 5 Sheets-Sheet5 Patented Feb. 19, 1929.

UNITED STATES 1,102,405 PATENT OFFICE.

EDWARD L. HOLMES, OF NEW YORK, N. Y., ASSIGNOR '10 HOLMES N AVIGLA'IINGAPPA- RATUS GO., INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

MASTER COMPASS.

Original application filed January 23, 1925, Serial No. 4,151. Dividedand this application filed .Tune 22, 1926. Serial No. 117,687.

My present application is adivisionof my application Serial No. 4,151,filed 1n the United States Patent Office on January 23, 1925. V

The following is a description of a mastercompass embodyingmy inventionin the form at present preferred by me; but it will be understood thatvarious modifications and changes may be made without departing 10 fromthe spirit of my invention and without exceeding the scope of my claims.

I My invention will best be understood by reference to theaccompanyingdrawings, in which I have illustrated the preferred form of. devices forcarrying out my invention, and

in which Fig. 1 shows schematically the several units comprising themaster-compass and a repeater-compass illustrative of mechanisms whichmay be actuated and controlled 20 by the said 1naster-compass-togetherwith a wiring diagram of an electrical system which may be employed inconnection therewith; Fig. 2 is a perspective view showing themaster-compass and associated mechanical and j, electrical devices; Fig.3 shows in vertical section the various elements of the magneticcompassand some of the elements of the master-compass and supporting means forsaid compasses; and Fig. 4 is a top plan view of the magnetic-compassand some of the master-compass elements and the supporting means. Likereference characters indicate like parts throughout the drawings.

Referring to the drawings (Fig. 3), 1 indicates a liquid typemagnetic-compass comprising magnetic needles 2 and 2, mounted upon arms3, carried by conical hub 4 (preferably of glass), containing jewel 5,forming a bearing for pivot'6, supported on post 7 integral withfollow-up compass bowl 8,

formed of insulating material, such as glass.

Arms 3 also carry annulus 9, preferably of mica, upon which aresupported magneticcompass card 10 (of material such as etched 5 orengraved brass which is insoluble in oil), and compasscard conductors l1and 11, both ends of which conductors project downwardly intoelectrolyte 12 contained in the lower portion of follow-up bowl 8.Floating upon V 5: this electrolyte is a body of liquid 13, which servesto insulate and protect the metallic compass structure, in a manner tobe hereinafter described. Integrally mounted in the periphery offollow-up bowl 8 and projecting into said-bowl are bowl conductors 14,

14 14 and 14. Follow-up bowl 8 carries 3), carrying follow-up bowl gear19 and distributor rings 20, 20 and 20 electrically insulated from saidbase and electrically connected to follow-up bowl conductors 14, 14, 14and 14. Attached to base 18 is shaft 21, operatively rotating in socket22 on upper platform 23 of frame 24, suspended by gimbals 25 and 25 togimbal-ring 26, supported by gimbals 27 and 27 on binnacle-ring 28,mounted on binnacle-stand 29. Also mounted on frame 24 is lubbers linebracket L, which has a lubbers line for the magneticcompass card andalso a lubbers line for the master-compass card. Mounted on upperplatform 23 and electrically insulated therefrom are three brushes 30,30 and 30 which operatively contact electrically with distributor rings20, 20 and 20 respectively. Attached to the under side of upper platform23 is follow-up motor 32, the armature shaft of which carries a worm(not shown) which drives a worm gear (not shown), mounted on shaft 33,which latter shaft also carries bevel pinion 34, meshing with anddriving bevel gear 35, mounted on vertical shaft 36. Vertical shaft 36carries at its upper end pinion 43, meshing with and driving follow-upbowl gear 19whereby follow-up motor 32 rotates said follow-up bowl.Follow-up motor 32 has differential field windings 44 and (Fig. 1 andreceives current from generator 46 or other suitable source ofelectrioal energy. The lower end of shaft 36 carries spur gear 37,meshing with and driving intermediate gear 38, integral with gear 39,mounted on a shaft having its bearing in lower platform 31 of frame 24,which gear 39 in turn meshes with and drives transmitter shaft gear40whereby follow-up motor 32 also rotates transmitter multiple brush 41,in electrical contact with transmitter distributor block 42.

The supply of current from source 46 to follow-up motor 32 is controlledby the. movements of armature 47 of relay48, whicharmature carriessprings 49 and 49. Attached to said armature are adjustable suspendedcontrolweights 50 and 50*, the purpose of which will be hereinafterexplained, The

. Current from the source 53 is conveyed through rotary transmitter 4142to the field \coils of reversible step-bystep motor 54,

causing said motor to rotate intermittently ineither direction, inawell-known manner.

While the apparatus will be described as operating one repeater-compassonly, it will --be=understood by those skilled in the art that it may beemployed to control any number of a such repeatencompasses, as well asother devices such as automatic steering mechanisn'i,

course-recorders and path-and-distance indi caters.

The mode of operation of the apparatus is as follows: Binnacle-stand 29is attached in the usual manner to a mobile object, such as a ship.

Initially, follow-up bowl 8 and magnetic needles 2 and 2 may not be inproper operative relationship; and in order to bring these elements intosuch relationship,

switch 55 is manually closed and relay armature 47 is manipulated toclose one or other of the circuits which include follow-up motor 32. Therotation of said follow-up motor in 1 the proper direction turnsfollow-up bowl 8,

i and thus brings bowl conductors 14 and 14 approximately opposite thedownwardly-projecting portions of compass card conductor 11; and bowlconductors 14 and 14 approximately opposite the downwardly-projectingportions of compass card conductor 11. This :operation also bringsmaster-compass card 17 into approximate alignment with magnetic-compasscard 10. Switch 56 is then manually closed, and the master-compass willthereafter automatically control the devices which may be electricallyconnected to it.

lVith bowl conductors and compass card conductors in alignment,substantially the same amount of current flows through the circuit whichincludes lines 57, cell 52,11ne 58, lines 59 and 60, compass bowlconductor 14, electrolyte 12, compass card conductor 11, electrolyte 12,bowl conductor 14, line 61, switch 56 and line 62 as flows through thecircuit which includes lines 57 and G3, coil 52, lines 64 and 65, bowlconductor 14 electrolyte 12, compass card conductor 11, electrolyte 12,bowl conductor 14 line 61, switch 56 and line 62. The energization ofrelay coils 52 and 52 is therefore practically equal, and relay armature47 remains in a neutral position in which it closes no secondarycircuit. After follow-up bowl 8 has beenbrought intopropor operativerelationship with compass needles 2 and 2 and before transmitter switch66 i closed, the ship is brought to its set path, which is indicatedboth by magnetic-compass card 10 andby-master-compass card 17-thedisplacement between magneticcompass card and master-compass cardresulting from turning the ship to its set path being corrected by the'action of follow-up motor 32, which operates to restore the synchronismof the two compass cards whenever there is a disturbance thereof.

With the ship on its set path (which, for purpose of illustration, willbe'assumed to be 50 east of north), the repeater-compass shown in Fig. 1is brought intosynchronism with the master-compass in the followingmanner With transmitter switch 66open, no current flows throughstep-by-step motor 54; and therepeater-compsss shaft, together with itsattached compass card, is freely rotatable. The repeater-compass shaftis now manually rotated until point 50 on the repeater-compass cardregisters with the repeater-compass lubbers line. When the ship isexactly on its course, as indicated by the fact that figure 50 onmaster-compass card registers with master-compass lubbers line,transmitter switch (36 is closed. This results in the energization ofsome of the field magnets of stepby-step motor 54, whereby therepeater-compass becomes electromagnetically locked to themaster-compass, and hence will subsequently follow all variations of themagneticcompass, because the magnetic-compass con trols themaster-con'ipass, which operates relay 48, the relay controls follow-upmotor 32 driving transmitter 4142, which in turn controls the directionand extent of rotation of step-by-step motor 54, driving therepeater-compass shaft. t will be'apparent that the apparatus isuniversally adjustable to opcrate with reference to any desired path towhich the repeater-compass shaft may be initially set.

Assuming now that the ship veers 1 to the right: Compass needles 2 and 2together with magnetic-compass card 10, will remain tionary in space,while the remainder of the compass structure, including follow-up bowl8,'will be displaced with reference to said compass needles, themovement of the bowl being in a clocllrwise direction. As soon as thisdisplacement reaches one-sixth of one degree, the device operates forthe reasons and in the manner following: Because of the form of bowlconductors 14, 14, 14 and 14, and of the compass card conductors 11 and11 respectively, and because of their relative positions, thisdisplacement by'one-sixth of one degree of follow-up bowl 8 does notmaterially change the length ofthe electrolytic paths between bowlconductors 14 and 14 and the coacting downwardly-projecting endsofcompass card conductor 11. Thererious external devices.

fore the resistance of the circuit which in cludes relaycoil 52 remainssubstantially unchanged. However, this clockwise movement of follow-upbowl 8 does increase the length of the electrolytic paths between bowlconductors 14c and 14 and the coacting downwardly-projecting ends ofcompass card conductor 11*, resulting in an increase in the re sistanceof the circuit which includes relay CO1l 52 and this mcrease 1nresistance reduces the energization of relay coil 52*, permitting relaycoil 52 to attract relay armature 41-7 and bring the same into contactwith contact member 51. This closes the following circuit: From oneterminal of source 46, line 67, switch 55, lines 68 and 69, relayarmature 17, relay contact member 51, lines 70, 71, 7 2 and 73, motorfield winding 15, armature of motor 32, lines v7 4, 7 5 and 76, toopposite terminal of source 16. Thereupon, follow-up motor 32 rotates ina direction to return follow-up bowl 8 to a position wherein theresistances of the two electrolytic circuits which include relay coils52 and 52 reach such valuesas to substantially equalize the energizationof such coils and thus bring relay armature 4:7 to its neutral positionthereby opening the circuit which includes the followup motor andstopping said motor. While follow-up motor 32 was rotating follow-upbowl 8 in a counter-clockwise direction to re-establish the initialrelationship between compass needles 2 and 2, and the follow-up bowl andits elements, said motor was also rotating transmitter 4142, actuatingthe step-by-step motor 54, turning the repeater-compass shaft andthereby rotating the repeater compass in a counter-clockwise directionone-sixth of one degree with reference to its lubbers line. With eachsuccessive deviation of the ship by one-sixth of one degree, there is arecurrence of this cycle of operation, until the total deviation of theassumed 1 has occurred.

I am aware that it has heretofore been pro posed to utilize movementsrelative to the needle of a magnetic compass to actuate va- For example,many attempts have been made to cause such movements to close metalliccontacts in electric circuits. However, the force exerted by the earthsmagnetic field upon a compass needle is inadequate to afford sufficientpressure to close such contacts without seriously interfering withtheaction of the needle.

It has also been attempted to utilize as a portion ofelectric circuitscontrolled by movements relative to the needle of the magnetic compass,an electrolyte in which the magnetic needle is immersed-direct current,Ibeing. conveyed through two circuits which include the electrolyte. Ihave found that such an arrangement is inoperative, for. the reason thatany compass change imbalances the resistances of the electrolyticportions of the circuits, greatly disturbing the constantpolaritymagnetic field which is associated with every circuit carrying directcurrent, and thereby producing a deflection of the compass needle.Moreover, if indestructible conductors, such as carbon, be employed inan electrolyte, direct current decomposes the electrolyte, resulting inthe evolution of gases, which, in the form of bubbles, adhere to theconductors, the compass bowl, and the compass card. These bubblesproduce changes in resistance in the electrolytic circuits, and alsoresult'in friction and capillary attracion between the moving parts. Ifdirect current be employed, this evolution and deposit-ion of gasesoccurs with all combinations of electrolytes and conductors except wherepure metallic conductors are used in combination with an electrolytecontaining a salt of the metal comprising one of the conductors. Underthese conditions, gas bubbles do not collect, but a plating actionoccurs which results in the disintegration of the conductors whichconstitute the anodes, and in the building up of the conductors whichconstitute the cathodes.

It has also been attempted to cause a master-compass to follow amagnetic-compass by utilizing the differential in resistances beof thepath. This is not the fact, and such a master-compass cannot faithfullyreproduce movements relative to the compass needle.

In attempts to utilize movements relative to the magnetic-compassneedle, it has been proposed to convey electric current to theconductors through the pivotal bearing of the compass card. Such devicesare impracticable for the reason that the compass card bearing must,under this condition, necessarily be metallic and of very minute area;and therefore any slight jarring which tends to separate the bearingelements causes areing, with consequent fusion-thus quicklydestroyingthe bearing. In my apparatus, the current is conducted directly throughthe electrolyte and conductors which are separate from the compasspivot, thereby obviating the defects above referred to.

l overcome the objections inherent in systems wherein the compass needleor compass card is caused to close metallic contacts inelectric'circuits by allowing my compass card to move freely in a liquidand, without other physical external contact than the necessary pivotalbearing contact. The responsiveness of. thedirectional element of mycompass to the earths magnetic field is therefore not interfered with. I

Instead of employing directcurrent, with than that of direct current. Infact, I have found that by employing an electrolyte co1nposed of equalparts of distilled water and chemically-pure methyl alcohol, acidulatedwith chemically-pure hydrochloric acid to a point where the minimumresistance of the electrolytic circuit is from 1,000 to 2,000 ohms. incombination with alternating current of a frequency of 60 cycles persecond, and with a current density in platinum conductors of about .75of an ampere per square inch, there occurs no release oil gases as aresult of decomposition of the electrolyte. Such an electrolyte does notfreeze at ordinary temperatures, which is an important practicalconsideration. Further, under these condi tions, a very small movementrelative to the magnetic-compass needles produces a marked differentialbetween the resistances oi the two electrolytic circuits.

Referring to Fig. 3: In order to protect th metallic portions of thecompass card'(which portions ordinarily consists of iron, copper andbrass) from electrolysis, I so mount the compass card as to bring itabove the level of the electrolyte, and immerse it in a body of liquidof high dielectric strength, such as mineral oil, floating upon saidelectrolyte and not miscible tlIGlG\\'ltl1--tl1ll8 effectually insulating such metallic portions from current flowing through theelectrolyte. By so mounting the compass card, the only metallic portionsassociated therewith which are in contact with the electrolyte are theplatinum iridium pivot upon which the card is supported, and thedownwardly-projecting ends of the two platinum conductors 11 and 11.Under the conditions I have above described, neither platinum-iridiumnor platinum is subject to electrolysis, when entirely immersed in theelectrolyte. I have found, however, that at the juncture of theelectrolyte and the insulating liquid, gas bubbles 'lorm upon theplatinum conductors, which evidences decomposition at this point ofeither the electrolyte or the insulating liquid, or perhaps of both. Inorder to prevent this action, I preterably insulate the platinumconductors by fusing vitreous material thereon for some distance aboveand below the point where they are to contact with the juncture of theelectrolyte and the insulating liquid.

I utilize the differential between resistances of the two electrolyticcircuits to actuate a sens tive relay which, in turn, controls a follow-up motor driving both the follow-up bowl and a transmitter whichgovernsthe repeatercompasi-s. I am thus enabled to operate my app minewith a current as low as 35 milliamperes flowing through each of theelectrolytic circuitsthe relay responding to a differential as small as3 milliamperes. With a movement of the ship, and, therefore, of thecompass bowl, as slight as one-sixth of one degree, this relay closesthe circuit which ineludes the follow-up motor; and the motor thereuponturns the follow-up bowl and the repeater-eompass shaft one-sixth of onedegree in the opposite directiou-the rate oi this movement being greatlyin excessof the rate oi? movement of the ship. When the follow-up bowlhas been returned to its original. position, the "follow-up motorstopsthe equilibrium of the electrolytic circuits having been restored.As the ship continues to deviate Fron'i its set path, this step-by-stepcountor-rotation of the "follow-up bowl and of the repeater-compassshaft recurs at each onesixth of one degree-the relay each time openingthe follow-up motor circuit upon a restoration of the equilibrium inthe-electrolytic circuits. l"l'1cre'l ore, in my system, instead oi.attempting to utilize a progressively-ing electrolytic resistance causedby a continuing deviation of the ship (which resistance, as I haveexplained, is not'directly proportional to the changes in the length ofthe electrolytic path), I repeatedly utilize small, definite and uniformresistance changes to produce step-by-step movements throughout the timein which the deviation occurs. Thus. the fact that the electrolyticresistance is not directly proportional to the changes in the length ofthe electrolytic path becomes of no consequence in the operation of myapparatus, because such operation is by current increments anddecrements which are always correlated to the same differential inresistances.

in order to insure that the operative differential will ellect acontinuous contact between the relay armature contact members and theircoacting contact members, I over.- come the vibratory eil ect upon suchcontact of the alternating current passing through the relay coils byopposing gravitational force to the force of magnetic attraction of thearmature. l accomplish this result by suspending weights attached tothreads supported between both sides of the upper end of the armatureand stationary points. I have found that by this means. and by carryingthe armatare contact members on springs of suitable tension, aditlerential of 3 milliamperes will produce a continuous contact-allvibration between the armature contact members and their coactingcontact members being e1imi- 7 nated. Under these conditions, thevibration due to the alternating current is restricted to the armatureitself, and does not affect the continuity of contact.

That I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, a directional element, a container for said element,an electrolyte in said container, conducting means carried by saiddirectional element and in contact with the electrolyte, a source 01alternating current, conducting means carried by the container and incontact with the electrolyte, an electric circuit including saidelectrolyte, conducting means and source, and electro-responsive meansoperative on variation in the electrolytic resistance of said circuitproduced by relative movement between the conducting means.

2. In combination, a magnetic compass rose, a container for said rose,an electrolyte in said container, partially-insulated conducting meanscarried by said rose and in contact with the electrolyte, conductingmeans carried by the container and in contact With the electrolyte, asource of alternating current, conducting means carried by thecontainerand in contact With the electrolyte, an electric circuitincluding said electrolyte, conducting means and source, andelectro-responsive means operative 011 variation in the electrolyticresistance of said circuit produced by relative movement between theconducting means.

3. In combination, a directional element, a container for said element,an electrolyte in said container from which said directional element iselectrically insulated, a support for said directional element,conducting means carried by said support and in contact With theelectrolyte, a source of alternating current, conducting means carriedby the container and in contact with the electrolyte,

an electric circuit including said electrolyte, conducting means andsource, and electroresponsive means operative on variation in theelectrolytic resistance of said circuit produced by relative movementbetween the conducting means.

at. Means for initiating the reproduction in repeating apparatus ofdisplacement movements between a directional element and a mobile objectcarrying the same, said means including a container for the directionalelement, an electrolyte in said container, conducting means carried bysaid directional element and in contact with the electrolyte, a sourceof alternating current, conducting means carried by the container and incontact with the electrolyte, an electric circuit including saidelectrolyte, conducting means and source, and electro-responsive meansoperative on variation in the electrolytic resistance of said circuitproduced by movement of the mobile object relative to the directionalelement.

5. Means for initiating the reproduction in repeating apparatus ofdisplacement movements between a directional element and a mobile objectcarrying the same, said means including a container for the directionalelement, an electrolyte in the container from which the directionalelement is electrically insulated, a support for the directionalelement, conducting means carried by the support and in contact With theelectrolyte, a source of alternating current, conducting means carriedby the container and in contact With the electrolyte, electric circuitsincluding the electrolyte, the conducting means and the source, and alsoincluding the Windings of a differential relay operative on varia tionin the electrolytic resistance of the circuit produced by movement ofthe mobile object relative to the directional element.

EDWVARD L. HOLMES.

